Graf B, Thillard M J, Labat M L, Cros M, Milhaud G
C R Acad Hebd Seances Acad Sci D. 1976 Oct 18;283(9):1073-6.
In the osteopetrotic mutant rat "op", the white pulp of the spleen is poor in T lymphocytes, while the red pulp is hyperplastic in reaction to the aplastic bone marrow. Grafting of normal thymus into the mutant corrects these anomalies.